1. Field of the Invention
The present invention relates to an anchor bolt, a connecting nut, a clamping nut and an anchor to be attached to various types of skeletons such as concrete buildings and structures.
2. Background Art
In order to attach hanging objects such as air conditioners, lighting fixtures, and various types of pipes to an existing ceiling structure of a building such as that made of concrete, anchors intended to support the hanging objects are fixed to the ceiling structure. The anchors are fixed to not only the ceiling structure but also surfaces such as that of a wall or a floor. Conventionally known anchors used for this purpose are disclosed for example in Japanese Patent Application Laid-Open No. 10-231583 (1998) (patent literature 1), and in Japanese Patent Application Laid-Open No. 10-110475 (1998) (patent literature 2).
Referring for example to the anchor disclosed in patent literature 1, it includes a spreading sleeve, and a cone nut in the form of a truncated cone. The spreading sleeve is swaged to be integrated with a tip portion of a steel bar, and in which multiple slits extending in the axial direction from the tip of the spreading sleeve are defined. The edge of a smaller diameter of the cone nut is press-fitted into a tip portion of the spreading sleeve. Regarding placement of this anchor, the anchor is inserted into a concrete hole with the cone nut placed nearest the hole. Then, with the tip of the cone nut in contact with a bottom portion of the hole, the steel bar is struck for example with a hammer to drive the anchor into the hole. The strike with a hammer presses the cone nut into the spreading sleeve, so that the tip portion of the spreading sleeve spreads outwardly in the radius direction while cutting into a concrete wall and the like along the tapered surface of the cone nut. As a result, the anchor is fixed to a skeleton.
Referring to the anchor disclosed in patent literature 2, it includes an anchor socket fixedly pressed-fitted into a concrete hole, and an anchor bolt threaded into the anchor socket through an opening at one end portion of the anchor socket. A slit is defined in an opposite end portion of the anchor socket. A head is integrally provided at a tip portion of the shank of a shaft part of the anchor bolt. The head is press-fitted into the inner circumference of the opposite end portion of the anchor socket to causes the opposite end portion to spread. Regarding placement of this anchor, the anchor socket is inserted in advance into a concrete hole with the opposite end portion placed nearest the hole. Then, the anchor bolt is threadedly inserted into the anchor socket through the opening at the one end portion of the anchor socket. In response to the threaded insertion of the anchor bolt, the head at the tip portion of the anchor bolt causes the opposite end portion of the anchor socket to spread, thereby fixing the anchor.